There is known such a lens driving apparatus that drives an objective lens in a lens optical axis direction (or focus direction) in order to focus a reading beam on a disc surface, that drives the objective lens in an orthogonal direction (or tracking direction) orthogonal to the lens optical axis direction in order to make the reading beam follow an information track, and that drives the objective lens in a warping direction (or tilt direction) of the disc surface in order to irradiate the disc surface with the reading beam with the optical axis of the reading beam being perpendicular to the disc surface, when information is read from a disc on which the information is optically recorded. One example of such a lens driving apparatus is disclosed in a patent document 1 or the like. The lens driving apparatus is of a print coil type in which a planar coil substrate, formed by patterning and etching a focus coil and a tracking coil, is fixed by an adhesive to the both side surfaces of a lens holder with a built-in objective lens.
Patent document 1: Japanese Patent Application Laid Open NO. 2001-229557
Patent document 2: Japanese Patent Application Laid Open NO. 2006-31759